Well all know what it is. And chances are we all had it used on us. It's so asinine. The race card is just a last resort ignorant people use when they can't come up with a reasonable argument as to how exactly they aren't being treated fairly. So what is your best example of when someone really just had no way to defend themselves with something other than their race?
Here's mine: At work a Mexican family (English was obviously a language spoken early on, because it was very fluent) tried to return something that was bought new, used it, and still wanted their full refund back. Well, used is used. You can't return something new just because you didn't like it. That may work with clothes but not games. I told them the best I could do was a trade. Basically, they said that someone from the location closer to their home told them otherwise and that they could return the game should they want to and that I was denying them the same service because of their color. I told the woman that said the stupid thing that that was not the case. But she insisted that it was, gave me a smug look and walked on. She stood in front of the door and, I am guessing, just read the back of the receipt given to her because she left shortly after.
I'm sure she would've felt pretty fucking stupid had she known I was actually Mexican myself (albeit don't look it).